When other guitarists think theyre better than me because I'm not playing a gibson and a custom 7. Dudes around here are really bad for that. Yes, I play an ibanez 7 and an import Dillion PRS knockoff, but hey, dude, look whose band the crowd seems to like more...
Also, not necessarily a guitarist pet peeve, but when other people think that guitar is easy. And let me say, yes, guitar is easy. Why do you think there are so many people who play it? But when all the vocal majors in my school get on my case because my instrument is "easy":
fuoco - YouTube
Bitch, I dare you to play this...
It actually feels really good when people have to learn guitar for a music ed. class, and start to struggle playing 3 notes on the high e string.